curlgrep-notify/curlgrep.sh

#!/bin/bash

source "$(dirname $(readlink -f "$0"))/config.sh"

function do_notify {
    msg="$1"
    curl "http://[::1]:51641/plain" -F message="$msg"
}

function do_one {
    if [ "$#" -lt 4 ] ; then
        >&2 echo "Missing argument to do_one."
        return
    fi

    url="$1"
    pattern="$2"
    msg="$3"
    elt_id="$4"
    state_path="$STATE_DIR/$elt_id"

    echo -n "Polling $url… "

    curl -s "$url" | grep -q "$pattern"
    no_match="$?"

    if [ "$no_match" -eq 1 ]; then
        if [ -f "$state_path" ] ; then
            echo "no match anymore"
            rm -f "$state_path"
        else
            echo "still no match"
        fi
    else # match
        if ! [ -f "$state_path" ] ; then  # no previous match
            echo "now matches"
            touch "$state_path"
            do_notify "$msg"
        else
            echo "still matches"
        fi
    fi
}

if [ "${#URLS[@]}" -ne "${#PATTERNS[@]}" ] \
    || [ "${#URLS[@]}" -ne "${#MESSAGES[@]}" ]
then
    >&2 echo "Bad configuration: unbalanced number of elements"
    exit 2
fi
mkdir -p "$STATE_DIR"

for elt_id in "${!URLS[@]}"; do
    do_one \
        "${URLS[$elt_id]}" \
        "${PATTERNS[$elt_id]}" \
        "${MESSAGES[$elt_id]}" \
        "$elt_id"
done